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2002 chevy trailblazer_lt
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9 Posts
Discussion Starter #1
I have trouble for 2 winters with my 4 WD not working. The first trip to the dealer they replaced my 4 WD switch. This did not fix the problem. I kept having to pull the famous #8 fuse and my 4 WD worked for a little while so I had the dealer replace the TCCM under the dash. I no longer have to pull #8 fuse. Now when I try to put the vehicle in 4WD the light blinks 15 times then it goes to a solid light then a minute later the service 4WD comes on and I am not in 4WD so I put it in to 2 wheel high but the solid light stays on the 4WD. Then every time I turn the vehicle off and back on I do not get a service 4WD light until I try to put it in 4WD or AWD. Any ideas? The selector switch has been changed. The transfer case control module has been changed. The oil in transfer case has been changed. And my 4WD drive still doesn't work. Any ideas?
 

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2006 chevy trailblazer_ls
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32 Posts
Only other possibility is the actuator motor on Transfer Case or the wiring. The motor has sensors that tells the tccm it's position.
 

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Registered
2002 chevy trailblazer_lt
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9 Posts
Discussion Starter #3
I am seriously thinking of changing out the transfer case control motor module now that I have at least 1 other person that thinks the same way I do.
 

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2004 gmc envoy_slt
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2,249 Posts
Do not change the TCCM again. The problem could be the Encoder motor on the transfer case, the actuator on the front splined disconnect or a wiring issue.

When you switch from 2HI to 4HI do hear two distinct motor sounds? If you hear only one or if one takes a long time to end (more than 10 - 15 seconds), that may mean that one is bad.
 
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